The proposed research will investigate the nature of the perceptual processes involved in skilled reading. A computer-based eye movement controlled display system will be used to study these processes as people are actually involved in the act of reading. The computer will produce display changes in the text based on characteristics of the eye movements, meanwhile keeping a complete record of the reader's eye movements. Questions to be investigated include the following. Concerning the perceptual span: Are there individual differences in the size of the region from which visual information is acquired during a fixation? Does the size of this region vary at different points in the text, or as a function of the reader's task? Concerning the functional stimulus in reading: What aspects of the words are used in reading? Does this vary as a function of textural constraints, or as a function of the reader's task? Concerning events during the fixation: When during the fixation is visual information acquired while reading? Concerning eye movement guidance: What are the laws determining where the eye is sent for a fixation during reading?